Add a rule under page and post titles, and tags shown with a # in front

Two Design tab options in the Posts section. The title rule reuses the
header rule's kinds (line, dots, stripes): a body class blog.css draws
from — width and style only, so the theme CSS's link colour is not reset —
ending at a floated thumbnail instead of running under it. The tag hash is
applied everywhere tags are listed: under posts, in both tag modules and in
the tag page's title.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Sd8UPWrvyYCLj97JexNw3A

1 files changed, 17 insertions, 0 deletions

diff --git a/internal/web/web_test.go b/internal/web/web_test.go
index 42d29e4..205e42f 100644
--- a/internal/web/web_test.go
+++ b/internal/web/web_test.go
@@ -133,6 +133,23 @@ func TestThemeNormalizeAndCSS(t *testing.T) {
 	}
 }
 
+// The rule under titles is a body class blog.css draws from, coloured by the
+// theme CSS; the tag hash is a plain flag the templates read.
+func TestTitleRuleAndTagHash(t *testing.T) {
+	th := DefaultTheme()
+	if th.TitleRuleClass() != "" || th.TagHash || strings.Contains(th.CSS(), ".page-title") {
+		t.Errorf("defaults: %+v", th)
+	}
+	th = ThemeFromForm(th, url.Values{"title_rule": {"dots"}, "tag_hash": {"on"}, "link_color": {"#b03a48"}})
+	if th.TitleRuleClass() != "titles-dots" || !th.TagHash || !strings.Contains(th.CSS(), ".page-title, .post-title { border-color:#b03a48; }") {
+		t.Errorf("from form: %+v\n%s", th, th.CSS())
+	}
+	th = ThemeFromForm(th, url.Values{"title_rule": {"neon"}})
+	if th.TitleRuleClass() != "" || th.TagHash {
+		t.Errorf("junk rule falls back, unticked box is off: %+v", th)
+	}
+}
+
 // An uploaded font is declared as a face and put first in the stack, the
 // built-in choice behind it; the heading font falls back to the text's stack.
 func TestCustomFontCSS(t *testing.T) {